Surgical instrument having knife band with curved distal edge

ABSTRACT

An end effector for operating on tissue comprises a first jaw, a second jaw, a firing beam, and a support band. The first jaw is movable toward the second jaw to capture tissue. The first jaw has a first slot and the second jaw has a second slot. The firing beam and the support band are coupled together and are positioned to translate through the first and second slots of the jaws. The firing beam presents a sharp distal edge for severing tissue captured between the jaws. The support band presents a curved distal end. The sharp distal edge of the firing beam is partially covered and partially exposed by the curved distal end of the support band.

BACKGROUND

A variety of surgical instruments include a tissue cutting element and one or more elements that transmit radio frequency (RF) energy to tissue (e.g., to coagulate or seal the tissue). An example of such an electrosurgical instrument is the ENSEAL® Tissue Sealing Device by Ethicon Endo-Surgery, Inc., of Cincinnati, Ohio. Further examples of such devices and related concepts are disclosed in U.S. Pat. No. 6,500,176 entitled “Electrosurgical Systems and Techniques for Sealing Tissue,” issued Dec. 31, 2002, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 7,112,201 entitled “Electrosurgical Instrument and Method of Use,” issued Sep. 26, 2006, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 7,125,409, entitled “Electrosurgical Working End for Controlled Energy Delivery,” issued Oct. 24, 2006, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 7,169,146 entitled “Electrosurgical Probe and Method of Use,” issued Jan. 30, 2007, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 7,186,253, entitled “Electrosurgical Jaw Structure for Controlled Energy Delivery,” issued Mar. 6, 2007, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 7,189,233, entitled “Electrosurgical Instrument,” issued Mar. 13, 2007, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 7,220,951, entitled “Surgical Sealing Surfaces and Methods of Use,” issued May 22, 2007, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 7,309,849, entitled “Polymer Compositions Exhibiting a PTC Property and Methods of Fabrication,” issued Dec. 18, 2007, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 7,311,709, entitled “Electrosurgical Instrument and Method of Use,” issued Dec. 25, 2007, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 7,354,440, entitled “Electrosurgical Instrument and Method of Use,” issued Apr. 8, 2008, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 7,381,209, entitled “Electrosurgical Instrument,” issued Jun. 3, 2008, the disclosure of which is incorporated by reference herein.

Additional examples of electrosurgical cutting instruments and related concepts are disclosed in U.S. Pub. No. 2011/0087218, entitled “Surgical Instrument Comprising First and Second Drive Systems Actuatable by a Common Trigger Mechanism,” published Apr. 14, 2011, issued as U.S. Pat. No. 8,939,974 on Jan. 27, 2015, the disclosure of which is incorporated by reference herein; U.S. Pub. No. 2012/0083783, entitled “Surgical Instrument with Jaw Member,” published Apr. 5, 2012, issued as U.S. Pat. No. 8,888,809 on Nov. 18, 2014, the disclosure of which is incorporated by reference herein; U.S. Pub. No. 2012/0116379, entitled “Motor Driven Electrosurgical Device with Mechanical and Electrical Feedback,” published May 10, 2012, issued as U.S. Pat. No. 9,161,803 on Oct. 20, 2015, the disclosure of which is incorporated by reference herein; U.S. Pub. No. 2012/0078243, entitled “Control Features for Articulating Surgical Device,” published Mar. 29, 2012, the disclosure of which is incorporated by reference herein; U.S. Pub. No. 2012/0078247, entitled “Articulation Joint Features for Articulating Surgical Device,” published Mar. 29, 2012, the disclosure of which is incorporated by reference herein; U.S. Pub. No. 2013/0030428, entitled “Surgical Instrument with Multi-Phase Trigger Bias,” published Jan. 31, 2013, issued as U.S. Pat. No. 9,089,327 on Jul. 28, 2015, the disclosure of which is incorporated by reference herein; and U.S. Pub. No. 2013/0023868, entitled “Surgical Instrument with Contained Dual Helix Actuator Assembly,” published Jan. 31, 2013, the disclosure of which is incorporated by reference herein.

While a variety of surgical instruments have been made and used, it is believed that no one prior to the inventors has made or used the invention described in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims which particularly point out and distinctly claim this technology, it is believed this technology will be better understood from the following description of certain examples taken in conjunction with the accompanying drawings, in which like reference numerals identify the same elements and in which:

FIG. 1 depicts a side elevational view of an exemplary electrosurgical medical instrument;

FIG. 2 depicts a perspective view of the end effector of the instrument of FIG. 1, in an open configuration;

FIG. 3 depicts another perspective view of the end effector of the instrument of FIG. 1, in an open configuration;

FIG. 4 depicts a cross-sectional end view of the end effector of FIG. 2, taken along line 4-4 of FIG. 3, in a closed configuration and with the blade in a distal position;

FIG. 5 depicts a partial perspective view of the distal end of an exemplary alternative firing beam suitable for incorporation in the instrument of FIG. 1;

FIG. 6 depicts a perspective view of an exemplary alternative end effector suitable for incorporation in the instrument of FIG. 1, having an exemplary alternative firing beam;

FIG. 7 depicts a perspective view of the firing beam of FIG. 6;

FIG. 8 depicts another perspective view of the firing beam of FIG. 6;

FIG. 9 depicts an exploded perspective view of the end effector of FIG. 6; and

FIG. 10 depicts a top plan view of the end effector of FIG. 6.

The drawings are not intended to be limiting in any way, and it is contemplated that various embodiments of the technology may be carried out in a variety of other ways, including those not necessarily depicted in the drawings. The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present technology, and together with the description serve to explain the principles of the technology; it being understood, however, that this technology is not limited to the precise arrangements shown.

DETAILED DESCRIPTION

The following description of certain examples of the technology should not be used to limit its scope. Other examples, features, aspects, embodiments, and advantages of the technology will become apparent to those skilled in the art from the following description, which is by way of illustration, one of the best modes contemplated for carrying out the technology. As will be realized, the technology described herein is capable of other different and obvious aspects, all without departing from the technology. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not restrictive.

It is further understood that any one or more of the teachings, expressions, embodiments, examples, etc. described herein may be combined with any one or more of the other teachings, expressions, embodiments, examples, etc. that are described herein. The following-described teachings, expressions, embodiments, examples, etc. should therefore not be viewed in isolation relative to each other. Various suitable ways in which the teachings herein may be combined will be readily apparent to those of ordinary skill in the art in view of the teachings herein. Such modifications and variations are intended to be included within the scope of the claims.

For clarity of disclosure, the terms “proximal” and “distal” are defined herein relative to a surgeon or other operator grasping a surgical instrument having a distal surgical end effector. The term “proximal” refers the position of an element closer to the surgeon or other operator and the term “distal” refers to the position of an element closer to the surgical end effector of the surgical instrument and further away from the surgeon or other operator.

I. Exemplary Electrosurgical Device with Articulation Feature

FIGS. 1-4 show an exemplary electrosurgical instrument (10) that is constructed and operable in accordance with at least some of the teachings of U.S. Pat. Nos. 6,500,176; 7,112,201; 7,125,409; 7,169,146; 7,186,253; 7,189,233; 7,220,951; 7,309,849; 7,311,709; 7,354,440; 7,381,209; U.S. Pub. No. 2011/0087218(now U.S. Pat. No. 8,938,974); U.S. Pub. No. 2012/0083783(now U.S. Pat. No. 8,888,809); U.S. Pub. No. 2012/0116379(now U.S. Pat. No. 9,161,803); U.S. Pub. No. 2012/0078243; U.S. Pub. No. 2012/0078247; U.S. Pub. No. 2013/0030428(now U.S. Pat. No. 9,089,327); and/or U.S. Pub. No. 2013/0023868. As described therein and as will be described in greater detail below, electrosurgical instrument (10) is operable to cut tissue and seal or weld tissue (e.g., a blood vessel, etc.) substantially simultaneously. In other words, electrosurgical instrument (10) operates similar to an endocutter type of stapler, except that electrosurgical instrument (10) provides tissue welding through application of bipolar RF energy instead of providing lines of staples to join tissue. It should also be understood that electrosurgical instrument (10) may have various structural and functional similarities with the ENSEAL® Tissue Sealing Device by Ethicon Endo-Surgery, Inc., of Cincinnati, Ohio. Furthermore, electrosurgical instrument (10) may have various structural and functional similarities with the devices taught in any of the other references that are cited and incorporated by reference herein. To the extent that there is some degree of overlap between the teachings of the references cited herein, the ENSEAL® Tissue Sealing Device by Ethicon Endo-Surgery, Inc., of Cincinnati, Ohio, and the following teachings relating to electrosurgical instrument (10), there is no intent for any of the description herein to be presumed as admitted prior art. Several teachings below will in fact go beyond the scope of the teachings of the references cited herein and the ENSEAL® Tissue Sealing Device by Ethicon Endo-Surgery, Inc., of Cincinnati, Ohio.

A. Exemplary Handpiece and Shaft

Electrosurgical instrument (10) of the present example includes a handpiece (20), a shaft (30) extending distally from handpiece (20), and an end effector (40) disposed at a distal end of shaft (30). Handpiece (20) of the present example includes a pistol grip (22), a pivoting trigger (24), an activation button (26), and an articulation control (28). Trigger (24) is pivotable toward and away from pistol grip (22) to selectively actuate end effector (40) as will be described in greater detail below. Activation button (26) is operable to selectively activate RF circuitry that is in communication with end effector (40), as will also be described in greater detail below. In some versions, activation button (26) also serves as a mechanical lockout against trigger (24), such that trigger (24) cannot be fully actuated unless button (26) is being pressed simultaneously. Examples of how such a lockout may be provided are disclosed in one or more of the references cited herein. In addition or in the alternative, trigger (24) may serve as an electrical and/or mechanical lockout against button (26), such that button (26) cannot be effectively activated unless trigger (24) is being squeezed simultaneously. It should be understood that pistol grip (22), trigger (24), and button (26) may be modified, substituted, supplemented, etc. in any suitable way, and that the descriptions of such components herein are merely illustrative.

Shaft (30) of the present example includes a rigid outer sheath (32) and an articulation section (36). Articulation section (36) is operable to selectively laterally deflect end effector (40) at various angles relative to the longitudinal axis defined by sheath (32). In some versions, articulation section (36) and/or some other portion of outer sheath (32) includes a flexible outer sheath (e.g., a heat shrink tube, etc.) disposed about its exterior. Articulation section (36) of shaft (30) may take a variety of forms. By way of example only, articulation section (36) may be configured in accordance with one or more teachings of U.S. Pub. No. 2012/0078247, the disclosure of which is incorporated by reference herein. As another merely illustrative example, articulation section (36) may be configured in accordance with one or more teachings of U.S. Pub. No. 2012/0078248, issued as U.S. Pat. No. 9,220,559 on Dec. 29, 2015, entitled “Articulation Joint Features for Articulating Surgical Device,” published Mar. 29, 2012, the disclosure of which is incorporated by reference herein. Various other suitable forms that articulation section (36) may take will be apparent to those of ordinary skill in the art in view of the teachings herein. It should also be understood that some versions of instrument (10) may simply lack articulation section (36).

In some versions, shaft (30) is also rotatable about the longitudinal axis defined by sheath (32), relative to handpiece (20), via a knob (34). Such rotation may provide rotation of end effector (40) and shaft (30) unitarily. In some other versions, knob (34) is operable to rotate end effector (40) without rotating articulation section (36) or any portion of shaft (30) that is proximal of articulation section (36). As another merely illustrative example, electrosurgical instrument (10) may include one rotation control that provides rotatability of shaft (30) and end effector (40) as a single unit; and another rotation control that provides rotatability of end effector (40) without rotating articulation section (36) or any portion of shaft (30) that is proximal of articulation section (36). Other suitable rotation schemes will be apparent to those of ordinary skill in the art in view of the teachings herein. Of course, rotatable features may simply be omitted if desired.

Articulation control (28) of the present example is operable to selectively control articulation section (36) of shaft (30), to thereby selectively laterally deflect end effector (40) at various angles relative to the longitudinal axis defined by shaft (30). While articulation control (28) is in the form of a rotary dial in the present example, it should be understood that articulation control (28) may take numerous other forms. By way of example only, some merely illustrative forms that articulation control (28) and other components of handpiece (20) may take are disclosed in U.S. Pub. No. 2012/0078243, the disclosure of which is incorporated by reference herein; in U.S. Pub. No. 2012/0078244, entitled “Control Features for Articulating Surgical Device,” published Mar. 29, 2012, the disclosure of which is incorporated by reference herein; and in U.S. Pub. No. 2013/0023868, the disclosure of which is incorporated by reference herein. Still other suitable forms that articulation control (28) may take will be apparent to those of ordinary skill in the art in view of the teachings herein. It should also be understood that some versions of instrument (10) may simply lack an articulation control (28).

B. Exemplary End Effector

End effector (40) of the present example comprises a first jaw (42) and a second jaw (44). In the present example, first jaw (42) is substantially fixed relative to shaft (30); while second jaw (44) pivots relative to shaft (30), toward and away from first jaw (42). Use of the term “pivot” should not be read as necessarily requiring pivotal movement about a fixed axis. In some versions, second jaw (44) pivots about an axis that is defined by a pin (or similar feature) that slides along an elongate slot or channel as second jaw (44) moves toward first jaw (42). In such versions, the pivot axis translates along the path defined by the slot or channel while second jaw (44) simultaneously pivots about that axis. It should be understood that such sliding/translating pivotal movement is encompassed within terms such as “pivot,” “pivots,” “pivotal,” “pivotable,” “pivoting,” and the like. Of course, some versions may provide pivotal movement of second jaw (44) about an axis that remains fixed and does not translate within a slot or channel, etc.

In some versions, actuators such as rods or cables, etc., may extend through sheath (32) and be joined with second jaw (44) at a pivotal coupling (43), such that longitudinal movement of the actuator rods/cables/etc. through shaft (30) provides pivoting of second jaw (44) relative to shaft (30) and relative to first jaw (42). Of course, jaws (42, 44) may instead have any other suitable kind of movement and may be actuated in any other suitable fashion. By way of example only, and as will be described in greater detail below, jaws (42, 44) may be actuated and thus closed by longitudinal translation of a firing beam (60), such that actuator rods/cables/etc. may simply be eliminated in some versions.

As best seen in FIGS. 2-4, first jaw (42) defines a longitudinally extending elongate slot (46); while second jaw (44) also defines a longitudinally extending elongate slot (48). In addition, the top side of first jaw (42) presents a first electrode surface (50); while the underside of second jaw (44) presents a second electrode surface (52). Electrode surfaces (50, 52) are in communication with an electrical source (80) via one or more conductors (not shown) that extend along the length of shaft (30). These conductors are coupled with electrical source (80) and a controller (82) via a cable (84), which extends proximally from handpiece (20). Electrical source (80) is operable to deliver RF energy to first electrode surface (50) at an active polarity while second electrode surface (52) serves as a reference/return passive electrode, such that RF current flows between electrode surfaces (50, 52) and thereby through tissue captured between jaws (42, 44). There are instances where the active signal crosses zero potential that the reference is at the same potential so there is no current flow. In some versions, firing beam (60) serves as an electrical conductor that cooperates with electrode surfaces (50, 52) (e.g., as a ground return) for delivery of bipolar RF energy captured between jaws (42, 44). Electrical source (80) may be external to electrosurgical instrument (10) or may be integral with electrosurgical instrument (10) (e.g., in handpiece (20), etc.), as described in one or more references cited herein or otherwise. A controller (82) regulates delivery of power from electrical source (80) to electrode surfaces (50, 52). Controller (82) may also be external to electrosurgical instrument (10) or may be integral with electrosurgical instrument (10) (e.g., in handpiece (20), etc.), as described in one or more references cited herein or otherwise. It should also be understood that electrode surfaces (50, 52) may be provided in a variety of alternative locations, configurations, and relationships.

By way of example only, power source (80) and/or controller (82) may be configured in accordance with at least some of the teachings of U.S. Provisional Pat. App. No. 61/550,768, entitled “Medical Instrument,” filed Oct. 24, 2011, the disclosure of which is incorporated by reference herein; U.S. Pub. No. 2011/0082486, entitled “Devices and Techniques for Cutting and Coagulating Tissue,” published Apr. 7, 2011, issued as U.S. Pat. No. 9,089,360 on Jul. 28, 2015, the disclosure of which is incorporated by reference herein; U.S. Pub. No. 2011/0087212, entitled “Surgical Generator for Ultrasonic and Electrosurgical Devices,” published Apr. 14, 2011, issued as U.S. Pat. No. 8,986,302 on Mar. 24, 2015, the disclosure of which is incorporated by reference herein; U.S. Pub. No. 2011/0087213, entitled “Surgical Generator for Ultrasonic and Electrosurgical Devices,” published Apr. 14, 2011, issued as U.S. Pat. No. 8,951,248 on Feb. 10, 2015, the disclosure of which is incorporated by reference herein; U.S. Pub. No. 2011/0087214, entitled “Surgical Generator for Ultrasonic and Electrosurgical Devices,” published Apr. 14, 2011, issued as U.S. Pat. No. 9,039,695 on May 26, 2015, the disclosure of which is incorporated by reference herein; U.S. Pub. No. 2011/0087215, entitled “Surgical Generator for Ultrasonic and Electrosurgical Devices,” published Apr. 14, 2011, issued as U.S. Pat. No. 9,050,093 on Jun. 9, 2015, the disclosure of which is incorporated by reference herein; U.S. Pub. No. 2011/0087216, entitled “Surgical Generator for Ultrasonic and Electrosurgical Devices,” published Apr. 14, 2011, issued as U.S. Pat. No. 8,956,349 on Feb. 17, 2015, the disclosure of which is incorporated by reference herein; and/or U.S. Pub. No. 2011/0087217, entitled “Surgical Generator for Ultrasonic and Electrosurgical Devices,” published Apr. 14, 2011, issued as U.S. Pat. No. 9,060,776 on Jun. 23, 2015, the disclosure of which is incorporated by reference herein. Other suitable configurations for power source (80) and controller (82) will be apparent to those of ordinary skill in the art in view of the teachings herein.

As best seen in FIG. 4, the lower side of first jaw (42) includes a longitudinally extending recess (58) adjacent to slot (46); while the upper side of second jaw (44) includes a longitudinally extending recess (59) adjacent to slot (48). FIG. 2 shows the upper side of first jaw (42) including a plurality of teeth serrations (55). It should be understood that the lower side of second jaw (44) may include complementary serrations that nest with serrations (55), to enhance gripping of tissue captured between jaws (42, 44) without necessarily tearing the tissue. In other words, it should be understood that serrations may be generally blunt or otherwise atraumatic. FIG. 3 shows an example of serrations (56) in first jaw (42) as mainly recesses; with serrations (54) in second jaw (44) as mainly protrusions. Of course, serrations (54, 56) may take any other suitable form or may be simply omitted altogether. It should also be understood that serrations (54, 56) may be formed of an electrically non-conductive, or insulative, material, such as plastic, glass, and/or ceramic, for example, and may include a treatment such as polytetrafluoroethylene, a lubricant, or some other treatment to substantially prevent tissue from getting stuck to jaws (42, 44). In some versions, serrations (54, 56) are electrically conductive.

With jaws (42, 44) in a closed position, shaft (30) and end effector (40) are sized and configured to fit through trocars having various inner diameters, such that electrosurgical instrument (10) is usable in minimally invasive surgery, though of course electrosurgical instrument (10) could also be used in open procedures if desired. By way of example only, with jaws (42, 44) in a closed position, shaft (30) and end effector (40) may present an outer diameter of approximately 5 mm. Alternatively, shaft (30) and end effector (40) may present any other suitable outer diameter (e.g., between approximately 2 mm and approximately 20 mm, etc.).

As another merely illustrative variation, either jaw (42, 44) or both of jaws (42, 44) may include at least one port, passageway, conduit, and/or other feature that is operable to draw steam, smoke, and/or other gases/vapors/etc. from the surgical site. Such a feature may be in communication with a source of suction, such as an external source or a source within handpiece (20), etc. In addition, end effector (40) may include one or more tissue cooling features (not shown) that reduce the degree or extent of thermal spread caused by end effector (40) on adjacent tissue when electrode surfaces (50, 52) are activated. Various suitable forms that such cooling features may take will be apparent to those of ordinary skill in the art in view of the teachings herein.

In some versions, end effector (40) includes one or more sensors (not shown) that are configured to sense a variety of parameters at end effector (40), including but not limited to temperature of adjacent tissue, electrical resistance or impedance of adjacent tissue, voltage across adjacent tissue, forces exerted on jaws (42, 44) by adjacent tissue, etc. By way of example only, end effector (40) may include one or more positive temperature coefficient (PTC) thermistor bodies (55, 57) (e.g., PTC polymer, etc.), located adjacent to electrodes (50, 52) and/or elsewhere. Data from sensors may be communicated to controller (82). Controller (82) may process such data in a variety of ways. By way of example only, controller (82) may modulate or otherwise change the RF energy being delivered to electrode surfaces (50, 52), based at least in part on data acquired from one or more sensors at end effector (40). In addition or in the alternative, controller (82) may alert the user to one or more conditions via an audio and/or visual feedback device (e.g., speaker, lights, display screen, etc.), based at least in part on data acquired from one or more sensors at end effector (40). It should also be understood that some kinds of sensors need not necessarily be in communication with controller (82), and may simply provide a purely localized effect at end effector (40). For instance, a PTC thermistor bodies (55, 57) at end effector (40) may automatically reduce the energy delivery at electrode surfaces (50, 52) as the temperature of the tissue and/or end effector (40) increases, thereby reducing the likelihood of overheating. In some such versions, a PTC thermistor element is in series with power source (80) and electrode surface (50, 52); and the PTC thermistor provides an increased impedance (reducing flow of current) in response to temperatures exceeding a threshold. Furthermore, it should be understood that electrode surfaces (50, 52) may be used as sensors (e.g., to sense tissue impedance, etc.). Various kinds of sensors that may be incorporated into electrosurgical instrument (10) will be apparent to those of ordinary skill in the art in view of the teachings herein. Similarly various things that can be done with data from sensors, by controller (82) or otherwise, will be apparent to those of ordinary skill in the art in view of the teachings herein. Other suitable variations for end effector (40) will also be apparent to those of ordinary skill in the art in view of the teachings herein.

C. Exemplary Firing Beam

As also seen in FIGS. 2-4, electrosurgical instrument (10) of the present example includes a firing beam (60) that is longitudinally movable along part of the length of end effector (40). Firing beam (60) is coaxially positioned within shaft (30), extends along the length of shaft (30), and translates longitudinally within shaft (30) (including articulation section (36) in the present example), though it should be understood that firing beam (60) and shaft (30) may have any other suitable relationship. In some versions, a proximal end of firing beam (60) is secured to a firing tube or other structure within shaft (30); and the firing tube or other structure extends through the remainder of shaft (30) to handpiece (20) where it is driven by movement of trigger (24). Firing beam (60) includes a sharp distal blade (64), an upper flange (62), and a lower flange (66). As best seen in FIG. 4, distal blade (64) extends through slots (46, 48) of jaws (42, 44), with upper flange (62) being located above jaw (44) in recess (59) and lower flange (66) being located below jaw (42) in recess (58). The configuration of distal blade (64) and flanges (62, 66) provides an “I-beam” type of cross section at the distal end of firing beam (60). While flanges (62, 66) extend longitudinally only along a small portion of the length of firing beam (60) in the present example, it should be understood that flanges (62, 66) may extend longitudinally along any suitable length of firing beam (60). In addition, while flanges (62, 66) are positioned along the exterior of jaws (42, 44), flanges (62, 66) may alternatively be disposed in corresponding slots formed within jaws (42, 44). For instance, each jaw (42, 44) may define a “T”-shaped slot, with parts of distal blade (64) being disposed in one vertical portion of each “T”-shaped slot and with flanges (62, 66) being disposed in the horizontal portions of the “T”-shaped slots. Various other suitable configurations and relationships will be apparent to those of ordinary skill in the art in view of the teachings herein.

Distal blade (64) is substantially sharp, such that distal blade (64) will readily sever tissue that is captured between jaws (42, 44). Distal blade (64) is also electrically grounded in the present example, providing a return path for RF energy as described elsewhere herein. In some other versions, distal blade (64) serves as an active electrode.

The “I-beam” type of configuration of firing beam (60) provides closure of jaws (42, 44) as firing beam (60) is advanced distally. In particular, flange (62) urges jaw (44) pivotally toward jaw (42) as firing beam (60) is advanced from a proximal position (FIGS. 1-3) to a distal position (FIG. 4), by bearing against recess (59) formed in jaw (44). This closing effect on jaws (42, 44) by firing beam (60) may occur before distal blade (64) reaches tissue captured between jaws (42, 44). Such staging of encounters by firing beam (60) may reduce the force required to squeeze trigger (24) to actuate firing beam (60) through a full firing stroke. In other words, in some such versions, firing beam (60) may have already overcome an initial resistance required to substantially close jaws (42, 44) on tissue before encountering resistance from severing the tissue captured between jaws (42, 44). Of course, any other suitable staging may be provided.

In the present example, flange (62) is configured to cam against a ramp feature at the proximal end of jaw (44) to open jaw (44) when firing beam (60) is retracted to a proximal position and to hold jaw (44) open when firing beam (60) remains at the proximal position. This camming capability may facilitate use of end effector (40) to separate layers of tissue, to perform blunt dissections, etc., by forcing jaws (42, 44) apart from a closed position. In some other versions, jaws (42, 44) are resiliently biased to an open position by a spring or other type of resilient feature. While jaws (42, 44) close or open as firing beam (60) is translated in the present example, it should be understood that other versions may provide independent movement of jaws (42, 44) and firing beam (60). By way of example only, one or more cables, rods, beams, or other features may extend through shaft (30) to selectively actuate jaws (42, 44) independently of firing beam (60). Such jaw (42, 44) actuation features may be separately controlled by a dedicated feature of handpiece (20). Alternatively, such jaw actuation features may be controlled by trigger (24) in addition to having trigger (24) control firing beam (60). It should also be understood that firing beam (60) may be resiliently biased to a proximal position, such that firing beam (60) retracts proximally when a user relaxes their grip on trigger (24).

FIG. 5 shows an exemplary alternative firing beam (70), which may be readily substituted for firing beam (60). In this example, firing beam (70) comprises a blade insert (94) that is interposed between two beam plates (90, 92). Blade insert (94) includes a sharp distal edge (96), such that blade insert (94) will readily sever tissue that is captured between jaws (42, 44). Sharp distal edge (96) is exposed by a proximally extending recess (93) formed in plates (90, 92). A set of pins (72, 74, 76) are transversely disposed in plates (90, 92). Pins (72, 74) together effectively serve as substitutes for upper flange (62); while pin (76) effectively serves as a substitute for lower flange (66). Thus, pins (72, 74) bear against channel (59) of jaw (44), and pin (76) bears against channel (58) of jaw (42), as firing beam (70) is translated distally through slots (46, 48). Pins (72, 74, 76) of the present example are further configured to rotate within plates (90, 92), about the axes respectively defined by pins (72, 74, 76). It should be understood that such rotatability of pins (72, 74, 76) may provide reduced friction with jaws (42, 44), thereby reducing the force required to translate firing beam (70) distally and proximally in jaws (42, 44). Pin (72) is disposed in an angled elongate slot (98) formed through plates (90, 92), such that pin (72) is translatable along slot (98). In particular, pin (72) is disposed in the proximal portion of slot (98) as firing beam (70) is being translated distally. When firing beam (70) is translated proximally, pin (72) slides distally and upwardly in slot (98), increasing the vertical separation between pins (72, 76), which in turn reduces the compressive forces applied by jaws (42, 44) and thereby reduces the force required to retract firing beam (70). Pins (72, 74, 76) may be pinged, upended, or otherwise configured to provide further retention in the body of firing beam (70). Of course, firing beam (70) may have any other suitable configuration. By way of example only, firing beam (70) may be configured in accordance with at least some of the teachings of U.S. Pub. No. 2012/0083783(now U.S. Pat. No. 8,888,809), the disclosure of which is incorporated by reference herein.

D. Exemplary Operation

In an exemplary use, end effector (40) is inserted into a patient via a trocar. Articulation section (36) is substantially straight when end effector (40) and part of shaft (30) are inserted through the trocar. Articulation control (28) may then be manipulated to pivot or flex articulation section (36) of shaft (30) in order to position end effector (40) at a desired position and orientation relative to an anatomical structure within the patient. Two layers of tissue of the anatomical structure are then captured between jaws (42, 44) by squeezing trigger (24) toward pistol grip (22). Such layers of tissue may be part of the same natural lumen defining anatomical structure (e.g., blood vessel, portion of gastrointestinal tract, portion of reproductive system, etc.) in a patient. For instance, one tissue layer may comprise the top portion of a blood vessel while the other tissue layer may comprise the bottom portion of the blood vessel, along the same region of length of the blood vessel (e.g., such that the fluid path through the blood vessel before use of electrosurgical instrument (10) is perpendicular to the longitudinal axis defined by end effector (40), etc.). In other words, the lengths of jaws (42, 44) may be oriented perpendicular to (or at least generally transverse to) the length of the blood vessel. As noted above, flanges (62, 66) cammingly act to pivot jaw (44) toward jaw (42) when firing beam (60) is actuated distally by squeezing trigger (24) toward pistol grip (22). Jaws (42, 44) may be substantially clamping tissue before trigger (24) has swept through a full range of motion toward pistol grip (22), such that trigger (24) may continue pivoting toward pistol grip (22) through a subsequent range of motion after jaws (42, 44) have substantially clamped on the tissue.

With tissue layers captured between jaws (42, 44) firing beam (60) continues to advance distally by the user squeezing trigger (24) further toward pistol grip (22). As firing beam (60) continues to advance distally, distal blade (64) simultaneously severs the clamped tissue layers, resulting in separated upper layer portions being apposed with respective separated lower layer portions. In some versions, this results in a blood vessel being cut in a direction that is generally transverse to the length of the blood vessel. It should be understood that the presence of flanges (62, 66) immediately above and below jaws (42, 44), respectively, help keep jaws (42, 44) in a closed and tightly clamping position. In particular, flanges (62, 66) help maintain a significantly compressive force between jaws (42, 44). With severed tissue layer portions being compressed between jaws (42, 44), bipolar RF energy is applied to the tissue through electrode surfaces (50, 52) by the user depressing activation button (26). Thus, a bipolar RF current flows through the compressed regions of severed tissue layer portions. The bipolar RF energy delivered by power source (80) ultimately thermally welds the tissue layer portions on one side of firing beam (60) together and the tissue layer portions on the other side of firing beam (60) together.

In certain circumstances, the heat generated by activated electrode surfaces (50, 52) can denature the collagen within the tissue layer portions and, in cooperation with clamping pressure provided by jaws (42, 44), the denatured collagen can form a seal within the tissue layer portions. Thus, the severed ends of the natural lumen defining anatomical structure are hemostatically sealed shut, such that the severed ends will not leak bodily fluids. In some versions, electrode surfaces (50, 52) may be activated with bipolar RF energy before firing beam (60) even begins to translate distally and thus before the tissue is even severed. For instance, such timing may be provided in versions where button (26) serves as a mechanical lockout relative to trigger (24) in addition to serving as a switch between power source (80) and electrode surfaces (50, 52). Other suitable ways in which instrument (10) may be operable and operated will be apparent to those of ordinary skill in the art in view of the teachings herein.

II. Exemplary Alternative Firing Beam

In some versions of instrument (10), end effector (40) has a curved configuration, such that the distal tip of the end effector is laterally offset from the longitudinal axis of the shaft (30) to which the end effector (40) is coupled. Examples of curved versions of end effector (40) are disclosed in U.S. patent application Ser. No. 13/692,202, entitled “Surgical Instrument with Curved Blade Firing Path,” filed Dec. 3, 2012, issued as U.S. Pat. No. 9,078,677 on Jul. 14, 2015, the disclosure of which is incorporated by reference herein; U.S. patent application Ser. No. 13/749,889, entitled “End Effector with Compliant Clamping Jaw,” filed Jan. 25, 2013, issued as U.S. Pat. No. 9,149,325 on Oct. 6, 2015, the disclosure of which is incorporated by reference herein; and U.S. Pub. No. 2012/0083783(now U.S. Pat. No. 8,888,809), the disclosure of which is incorporated by reference herein. In versions of instrument (10) having a curved end effector (40), it may be desirable to provide protection of sharp distal edge (96) of blade insert (94) as firing beam (60, 70) slides along the length of the curved end effector (40). In such versions, it may also be desirable increase the bending strength of firing beam (60, 70). Various examples of how firing beam (60, 70) may be configured to protect sharp distal edge (96) of blade insert (94) and/or increase the bending strength of firing beam (60, 70) will be described in greater detail below; while still other examples will be apparent to those of ordinary skill in the art according to the teachings herein.

It should be understood that the firing beam examples described below may function substantially similar to firing beam (60, 70) described above. In particular, the firing beam examples described below may be used to drive jaws of the curved end effector (40) into a closed position and to sever tissue captured between the closed jaws. Although the firing beam described below is discussed in reference to a curved end effector (140), it should be understood that the same firing beam may be used in any other suitable end effector (40) including a substantially straight end effector (40) as discussed above.

FIG. 6 shows a merely illustrative example of a curved end effector (140) that may be readily incorporated into instrument (10). Curved end effector (140) of the present example comprises a first jaw (142) and a second jaw (144). It should be understood that curved end effector (140) functions substantially similar to end effector (40) described above. In particular, first jaw (142) is substantially fixed relative to a shaft (not shown); while second jaw (144) pivots relative to the shaft, toward and away from first jaw (142). Jaws (142, 144) are configured to grasp tissue and apply bipolar RF energy to grasped tissue, similar to jaws (42, 44) described above.

Curved end effector (140) of the present example further comprises a knife or firing beam (160). The distal end (162) of firing beam (160) presents a sharp distal blade (196). Sharp distal blade (196) is configured to readily sever tissue that is captured between jaws (142, 144). Firing beam (160) is coupled with a support band (170) on a first side of firing beam (160), thereby forming an assembly. As best seen in FIGS. 7-8, support band (170) presents a curved distal end (172) and a longitudinally extending slot (174) disposed at a distal end of support band (170). Slot (174) presents an opening (175) at the distal end of support band (170). Curved distal end (172) comprises a first curved arm or lip (172A) and a second curved arm or lip (172B) disposed on opposite sides of slot (174). Distal end (162) of firing beam (160) is positioned just proximal to curved lips (172A, 172B) such that distal blade (196) is partially covered by curved lips (172A, 172B). However, a portion of sharp distal blade (196) is exposed through opening (175) of longitudinal slot (174). Curved distal end (172) may be formed in numerous ways, including but not limited to stamping, bending, machining, metal injection molding, etc. Firing beam (160) and support band (170) are both formed of metal in the present example, though it should be understood that firing beam (160) and/or support band (170) may be formed of any other suitable material or combination of materials.

As best seen in FIGS. 9-10, first jaw (142) defines a first curved slot (146); while second jaw (144) defines a second curved slot (148). In some other versions, first and second jaws (142, 144) are curved yet slots (146, 148) are not curved (e.g., slots (146, 148) may extend only along a straight region of jaws (142, 144), etc.). In the present example, firing beam (160) and support band (170) are configured to translate longitudinally through curved slots (146, 148). First jaw (142) and second jaw (144) also define complementary curved channels (143) and (145). A set of pins (182, 184, 186) are transversely disposed in firing beam (160) and support band (170). It should be understood that pins (182, 184, 186) function substantially similar to pins (72, 74, 76) described above. In particular, pins (182, 184) bear against curved channel (145) of second jaw (143), and pin (186) bears against channel (145) of first jaw (142), to drive jaws (142, 144) of curved end effector (140) into a closed position and to sever captured tissue as firing beam (160) and support band (170) are translated distally through slots (146, 148). When jaws (142, 144) are in the closed position, RF energy can to be delivered into the tissue captured between jaws (142, 144) via electrodes in jaws (142, 144). Pins (182, 184, 186) of the present example are further configured to rotate within firing beam (160) and support band (170), about axes respectively defined by pins (182, 184, 186). It should be understood that such rotatability of pins (182, 184, 186) may provide reduced friction with jaws (142, 144), thereby reducing the force required to translate firing beam (160) and support band (170) distally and proximally within jaws (142, 144).

In the present example, pins (182, 184, 186) hold firing beam (160) and support band (170) adjacent to each other yet still permit some degree of longitudinal sliding of firing beam (160) and support band (170) relative to each other. For instance, as firing beam (160) and support band (170) are together advanced from a proximal, straight configuration to a distal, bent configuration, support band (170) may slide distally relative to firing beam (160), even if just slightly. In some other versions, firing beam (160) and support band (170) are bonded together such that there is no relative sliding between firing beam (160) and support band (170).

As best seen in FIG. 10, firing beam (160) is oriented with respect to support band (170) such that as firing beam (160) is translated distally through slots (146, 148), curved distal end (172) of support band (170) will engage an interior surface of slot (146) and/or an interior surface of slot (148), thereby preventing sharp distal edge (196) and distal end (162) of firing beam (160) from contacting the interior surface of slots (146, 148). It should be understood that, in the absence of curved lips (172A, 172B), sharp distal edge (196) might otherwise contact the interior surface of slots (146, 148), resulting in grinding, galling, and/or other similar types of effects. These effects might promote wear to the interior surface of slots (146, 148), promote wear to sharp distal edge (196), and/or increase the force required to advance firing beam (160) distally. The inclusion of curved lips (172A, 172B) may thus avoid at least some degree of wear to the interior surface of slots (146, 148), avoid at least some degree of wear to sharp distal edge (196), and/or decrease the force required to advance firing beam (160) distally. This may further increase the effective life of firing beam (160). In addition,

Although the present example comprises only a single support band (170) coupled to a first side of firing beam (160), it should be understood that a second support band (170) may be positioned on the other side of firing beam (160). It should also be appreciated that support band (170) may increase the bending strength of firing beam (160), particularly at distal end (160) of firing beam (160) where curved distal end (172) of support band (170) is located. This increase in bending strength may, among of things, cause firing beam (160) to be less prone to buckling when jaws (142, 144) are closed upon thick tissue and firing beam (160) is advanced distally through the tissue.

III. Miscellaneous

It should be understood that any of the versions of electrosurgical instrument (10) described herein may include various other features in addition to or in lieu of those described above. By way of example only, any of the devices herein may also include one or more of the various features disclosed in any of the various references that are incorporated by reference herein.

It should also be understood that any of the devices described herein may be modified to include a motor or other electrically powered device to drive an otherwise manually moved component. Various examples of such modifications are described in U.S. Pub. No. 2012/0116379, entitled “Motor Driven Electrosurgical Device with Mechanical and Electrical Feedback,” published May 10, 2012(now U.S. Pat. No. 9,161,803), the disclosure of which is incorporated by reference herein. Various other suitable ways in which a motor or other electrically powered device may be incorporated into any of the devices herein will be apparent to those of ordinary skill in the art in view of the teachings herein.

It should also be understood that any of the devices described herein may be modified to contain most, if not all, of the required components within the medical device itself. More specifically, the devices described herein may be adapted to use an internal or attachable power source instead of requiring the device to be plugged into an external power source by a cable. Various examples of how medical devices may be adapted to include a portable power source are disclosed in U.S. Provisional Application Ser. No. 61/410,603, filed Nov. 5, 2010, entitled “Energy-Based Surgical Instruments,” the disclosure of which is incorporated by reference herein. Various other suitable ways in which a power source may be incorporated into any of the devices herein will be apparent to those of ordinary skill in the art in view of the teachings herein.

While the examples herein are described mainly in the context of electrosurgical instruments, it should be understood that various teachings herein may be readily applied to a variety of other types of devices. By way of example only, the various teachings herein may be readily applied to other types of electrosurgical instruments, tissue graspers, tissue retrieval pouch deploying instruments, surgical staplers, surgical clip appliers, ultrasonic surgical instruments, etc. It should also be understood that the teachings herein may be readily applied to any of the instruments described in any of the references cited herein, such that the teachings herein may be readily combined with the teachings of any of the references cited herein in numerous ways. Other types of instruments into which the teachings herein may be incorporated will be apparent to those of ordinary skill in the art.

In versions where the teachings herein are applied to a surgical stapling instrument, it should be understood that the teachings herein may be combined with the teachings of one or more of the following, the disclosures of all of which are incorporated by reference herein: U.S. Pat. No. 4,805,823, entitled “Pocket Configuration for Internal Organ Staplers,” issued Feb. 21, 1989; U.S. Pat. No. 5,415,334, entitled “Surgical Stapler and Staple Cartridge,” issued May 16, 1995; U.S. Pat. No. 5,465,895, entitled “Surgical Stapler Instrument,” issued Nov. 14, 1995; U.S. Pat. No. 5,597,107, entitled “Surgical Stapler Instrument,” issued Jan. 28, 1997; U.S. Pat. No. 5,632,432, entitled “Surgical Instrument,” issued May 27, 1997; U.S. Pat. No. 5,673,840, entitled “Surgical Instrument,” issued Oct. 7, 1997; U.S. Pat. No. 5,704,534, entitled “Articulation Assembly for Surgical Instruments,” issued Jan. 6, 1998; U.S. Pat. No. 5,814,055, entitled “Surgical Clamping Mechanism,” issued Sep. 29, 1998; U.S. Pat. No. 6,978,921, entitled “Surgical Stapling Instrument Incorporating an E-Beam Firing Mechanism,” issued Dec. 27, 2005; U.S. Pat. No. 7,000,818, entitled “Surgical Stapling Instrument Having Separate Distinct Closing and Firing Systems,” issued Feb. 21, 2006; U.S. Pat. No. 7,143,923, entitled “Surgical Stapling Instrument Having a Firing Lockout for an Unclosed Anvil,” issued Dec. 5, 2006; U.S. Pat. No. 7,303,108, entitled “Surgical Stapling Instrument Incorporating a Multi-Stroke Firing Mechanism with a Flexible Rack,” issued Dec. 4, 2007; U.S. Pat. No. 7,367,485, entitled “Surgical Stapling Instrument Incorporating a Multistroke Firing Mechanism Having a Rotary Transmission,” issued May 6, 2008; U.S. Pat. No. 7,380,695, entitled “Surgical Stapling Instrument Having a Single Lockout Mechanism for Prevention of Firing,” issued Jun. 3, 2008; U.S. Pat. No. 7,380,696, entitled “Articulating Surgical Stapling Instrument Incorporating a Two-Piece E-Beam Firing Mechanism,” issued Jun. 3, 2008; U.S. Pat. No. 7,404,508, entitled “Surgical Stapling and Cutting Device,” issued Jul. 29, 2008; U.S. Pat. No. 7,434,715, entitled “Surgical Stapling Instrument Having Multistroke Firing with Opening Lockout,” issued Oct. 14, 2008; U.S. Pat. No. 7,721,930, entitled “Disposable Cartridge with Adhesive for Use with a Stapling Device,” issued May 25, 2010; U.S. Pub. No. 2010/0264193, entitled “Surgical Stapling

Instrument with An Articulatable End Effector,” published Oct. 21, 2010, now U.S. Patent No. 8,408,439, issued Apr. 2, 2013; and U.S. Pub. No. 2012/0239012, entitled “Motor-Driven Surgical Cutting Instrument with Electric Actuator Directional Control Assembly,” published Sep. 20, 2012, now U.S. Patent No. 8,453,914, issued Jun. 4, 2013. Other suitable ways in which the teachings herein may be applied to a surgical stapling instrument will be apparent to those of ordinary skill in the art in view of the teachings herein.

It should be understood that any one or more of the teachings, expressions, embodiments, examples, etc. described herein may be combined with any one or more of the other teachings, expressions, embodiments, examples, etc. that are described herein. The above-described teachings, expressions, embodiments, examples, etc. should therefore not be viewed in isolation relative to each other. Various suitable ways in which the teachings herein may be combined will be readily apparent to those of ordinary skill in the art in view of the teachings herein. Such modifications and variations are intended to be included within the scope of the claims.

It should be appreciated that any patent, publication, or other disclosure material, in whole or in part, that is said to be incorporated by reference herein is incorporated herein only to the extent that the incorporated material does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material.

Versions of the devices described above may have application in conventional medical treatments and procedures conducted by a medical professional, as well as application in robotic-assisted medical treatments and procedures. By way of example only, various teachings herein may be readily incorporated into a robotic surgical system such as the DAVINCI™ system by Intuitive Surgical, Inc., of Sunnyvale, Calif. Similarly, those of ordinary skill in the art will recognize that various teachings herein may be readily combined with various teachings of U.S. Pat. No. 5,792,135, entitled “Articulated Surgical Instrument For Performing Minimally Invasive Surgery With Enhanced Dexterity and Sensitivity,” issued Aug. 11, 1998, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 5,817,084, entitled “Remote Center Positioning Device with Flexible Drive,” issued Oct. 6, 1998, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 5,878,193, entitled “Automated Endoscope System for Optimal Positioning,” issued Mar. 2, 1999, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 6,231,565, entitled “Robotic Arm DLUS for Performing Surgical Tasks,” issued May 15, 2001, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 6,783,524, entitled “Robotic Surgical Tool with Ultrasound Cauterizing and Cutting Instrument,” issued Aug. 31, 2004, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 6,364,888, entitled “Alignment of Master and Slave in a Minimally Invasive Surgical Apparatus,” issued Apr. 2, 2002, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 7,524,320, entitled “Mechanical Actuator Interface System for Robotic Surgical Tools,” issued Apr. 28, 2009, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 7,691,098, entitled “Platform Link Wrist Mechanism,” issued Apr. 6, 2010, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 7,806,891, entitled “Repositioning and Reorientation of Master/Slave Relationship in Minimally Invasive Telesurgery,” issued Oct. 5, 2010, the disclosure of which is incorporated by reference herein; and/or U.S. Pat. No. 7,824,401, entitled “Surgical Tool With Writed Monopolar Electrosurgical End Effectors,” issued Nov. 2, 2010, the disclosure of which is incorporated by reference herein.

Versions described above may be designed to be disposed of after a single use, or they can be designed to be used multiple times. Versions may, in either or both cases, be reconditioned for reuse after at least one use. Reconditioning may include any combination of the steps of disassembly of the device, followed by cleaning or replacement of particular pieces, and subsequent reassembly. In particular, some versions of the device may be disassembled, and any number of the particular pieces or parts of the device may be selectively replaced or removed in any combination. Upon cleaning and/or replacement of particular parts, some versions of the device may be reassembled for subsequent use either at a reconditioning facility, or by a user immediately prior to a procedure. Those skilled in the art will appreciate that reconditioning of a device may utilize a variety of techniques for disassembly, cleaning/replacement, and reassembly. Use of such techniques, and the resulting reconditioned device, are all within the scope of the present application.

By way of example only, versions described herein may be sterilized before and/or after a procedure. In one sterilization technique, the device is placed in a closed and sealed container, such as a plastic or TYVEK bag. The container and device may then be placed in a field of radiation that can penetrate the container, such as gamma radiation, x-rays, or high-energy electrons. The radiation may kill bacteria on the device and in the container. The sterilized device may then be stored in the sterile container for later use. A device may also be sterilized using any other technique known in the art, including but not limited to beta or gamma radiation, ethylene oxide, or steam.

Having shown and described various embodiments of the present invention, further adaptations of the methods and systems described herein may be accomplished by appropriate modifications by one of ordinary skill in the art without departing from the scope of the present invention. Several of such potential modifications have been mentioned, and others will be apparent to those skilled in the art. For instance, the examples, embodiments, geometrics, materials, dimensions, ratios, steps, and the like discussed above are illustrative and are not required. Accordingly, the scope of the present invention should be considered in terms of the following claims and is understood not to be limited to the details of structure and operation shown and described in the specification and drawings. 

We claim:
 1. An apparatus including an end effector for operating on tissue, wherein the end effector comprises: (a) a first jaw, wherein the first jaw defines a first slot; (b) a second jaw, wherein the second jaw defines a second slot, wherein the first jaw is selectively pivotable toward and away from the second jaw; and (c) a firing beam assembly, wherein the firing beam assembly is translatable through the first and second slots, wherein the firing beam assembly comprises: (i) a firing beam, wherein the firing beam has a distal end, wherein the distal end of the firing beam includes a sharp edge, and (ii) a support band, wherein the support band has a distal end, wherein the distal end of the support band has a curved distal lip, wherein the curved distal lip curves around a portion of a distal-most end of the firing beam, wherein the distal end of the firing beam is disposed within the curved distal lip.
 2. The apparatus of claim 1, wherein the first jaw and the second jaw are curved.
 3. The apparatus of claim 2, wherein the first slot and the second slot are curved.
 4. The apparatus of claim 3, wherein the curved distal lip of the support band is configured to engage at least one of an interior curved surface of the first slot or an interior curved surface of the second slot.
 5. The apparatus of claim 1, wherein the firing beam assembly further comprises a plurality of pins positioned transversely in the firing beam and the support band, wherein at least one of the plurality of pins is operable to drive the first jaw toward the second jaw in response to distal advancement of the firing beam.
 6. The apparatus of claim 5, wherein the plurality of pins are rotatable within the firing beam and the support band.
 7. The apparatus of claim 1, wherein the support band presents a longitudinally extending slot having a distal opening at the distal end of the support band.
 8. The apparatus of claim 7, wherein the curved distal lip comprises a first curved lip and a second curved lip.
 9. The apparatus of claim 8, wherein the first curved lip and the second curved lip are separated by the longitudinally extending slot.
 10. The apparatus of claim 7, wherein the sharp edge of the firing beam is exposed through the distal opening of the longitudinally extending slot.
 11. The apparatus of claim 1, wherein the firing beam is configured to drive the first jaw toward the second jaw.
 12. The apparatus of claim 1, wherein the end effector comprises at least one electrode operable to apply radiofrequency (RF) energy to the tissue.
 13. The apparatus of claim 1, wherein the firing beam is slidable relative to the support band.
 14. The apparatus of claim 1, wherein at least a portion of the sharp edge is adjacent to the curved distal lip.
 15. The apparatus of claim 1, wherein the curved distal lip is oriented transversely in relation to the firing beam.
 16. The apparatus of claim 1, further comprising: (a) a handpiece; and (b) an elongate shaft, wherein the elongate shaft extends distally from the handpiece, and wherein the elongate shaft comprises a distal end, wherein the end effector is disposed at the distal end of the elongate shaft.
 17. An end effector for operating on tissue, wherein the end effector comprises: (a) a first curved jaw, wherein the first curved jaw defines a first curved slot; (b) a second curved jaw, wherein the second curved jaw defines a second curved slot, wherein the first curved jaw is selectively pivotable toward and away from the second curved jaw; and (c) a firing beam assembly, wherein the firing beam assembly is translatable through the first and second curved slots, wherein the firing beam assembly comprises: (i) a firing beam, wherein the firing beam has a distal end, wherein the distal end of the firing beam includes a sharp edge, and (ii) a support band, wherein the support band has a distal end, wherein the distal end of the support band has a laterally projecting lip, wherein the distal end of the firing beam is disposed within the laterally projecting lip, wherein the laterally projecting lip covers a first portion of the sharp edge, wherein a second portion of the sharp edge is exposed relative to the laterally projecting lip.
 18. The end effector of claim 17, wherein the laterally projecting lip comprises an upper portion and a lower portion, wherein the second portion of the sharp edge is exposed between the upper portion and the lower portion of the laterally projecting lip.
 19. An end effector for operating on tissue, wherein the end effector comprises: (a) a first curved jaw, wherein the first curved jaw defines a first curved slot, wherein the first curved slot is bound in part by a first edge; (b) a second curved jaw, wherein the second curved jaw defines a second curved slot, wherein the second curved slot is bound in part by a second edge, wherein the first curved jaw is selectively pivotable toward and away from the second curved jaw; and (c) a firing beam assembly, wherein the firing beam assembly is translatable through the first and second curved slots, wherein the firing beam assembly comprises: (i) a firing beam, wherein the firing beam has a distal end, wherein the distal end of the firing beam includes a sharp edge, and (ii) a support band, wherein the support band has a distal end, wherein the distal end of the support band has a first distal lip and a second distal lip, wherein the first distal lip is configured to bear against the first edge of the first curved jaw, wherein the second distal lip is configured to bear against the second edge of the second curved jaw, wherein the first and second distal lips extend across the distal end of the firing beam to thereby cover corresponding portions of the sharp edge of the firing beam.
 20. The end effector of claim 19, wherein the support band further defines a distal opening separating the first distal lip from the second distal lip, wherein part of the sharp edge of the firing beam is distally exposed through the distal opening of the support band. 